Effects Of Film Drip Irrigation On Photosynthesis And Growth Of Maize In Northeast China

Film drip irrigation technology is an important way to improve corn yield in Northeast China,change backward productivity,solve the problem of uneven rainfall during growth period and insufficient water supply during the key growth period of corn,and make full use of abundant land resources in Northeast China to ensure national food security.In order to further study the effects of film drip irrigation on corn photosynthesis and provide a theoretical basis for its scientific field management.Based on the field experiment,the study was carried out with two methods:film drip irrigation and non-film drip irrigation,plus local traditional planting as a control treatment.Photosynthetic and chlorophyll determination equipment provides technical support for research.On this basis,the effects of film drip irrigation on light response characteristics,photosynthetic gas exchange performance,corn growth,photosynthetic products and water use of maize were analyzed.The results are as follows:1.Effect of film drip irrigation on light response of maize?1?Film drip irrigation increased the dark respiration rate to enhance the physiological activity of maize.The filling period was 13.30%⁹2.52%and 10.43%⁵8.91%higher than surface drip irrigation and control treatment;Increasing the apparent quantum efficiency enhances the ability of maize to use weak light,the average value of heading-filling period is9.32%¹7.38%and 12.58%¹5.65%higher than surface drip irrigation and control treatment;The drip irrigation of the film makes the low light compensation value during the jointing-grouting period beneficial to the use of weak light in the corn,and its mean value is17.64%¹8.60%and 13.23%¹7.59%lower than the surface drip irrigation and the control treatment;Film drip irrigation improves the light saturation point at jointing-heading stage,which is beneficial to increase the dark reaction ability of corn;Film drip irrigation increased the maximum net photosynthetic rate during jointing-grouting,which was beneficial to enhance the maximum assimilation ability of maize.The dark respiration rate,light compensation point and maximum net photosynthetic rate showed a downward trend during jointing-filling,while the apparent quantum efficiency showed an upward trend.?2?Obtained from the light response curve,the drip irrigation of the film is conducive to the utilization of highlights during the jointing-grouting period of the corn;The stomatal conductance of film drip irrigation is significantly higher than that of the control treatment,which is beneficial to corn photosynthetic gas exchange;Film drip irrigation weakened the transpiration of corn to a certain extent,the transpiration rate photoresponse showed surface drip irrigation>film drip irrigation>control treatment.The effective radiation in the range of0²100?mol m^-2 s^-1,the net photosynthetic rate,stomatal conductance and transpiration rate increased first and then stabilized with the increase of light intensity,and the intercellular CO₂concentration decreased first and then stabilized.2.Effect of film drip irrigation on photosynthetic gas exchange performance of maize?1?The gas exchange parameters such as net photosynthetic rate,stomatal conductance and transpiration rate increase first and then decrease with the growth period of corn,the peak and minimum values?intercellular CO₂ concentration?of the gas exchange parameters of each treatment occurred in the jointing-heading stage.Film drip irrigation improves net photosynthetic rate and stomatal conductance during growth period,the average net photosynthetic rate during the growth period was 7.58%¹0.50%and 18.79%²5.08%higher than the surface drip irrigation and control treatment;The film drip irrigation slightly reduced the transpiration rate and intercellular CO₂ concentration of the corn.?2?In the daily variation measurement,the net photosynthetic rate,stomatal conductance and transpiration rate of corn showed a“single peak”change,the peak appeared at 10:00¹2:00,and the peak of transpiration rate appeared at 14:00;Light has a great influence on photosynthetic performance,and the net photosynthetic rate decreases rapidly with the decrease of light intensity;The intercellular CO₂ concentration remained low from 8:00 to 14:00;the peak water use efficiency of single leaves appeared in the morning and evening.The average daily net photosynthetic rate of film drip irrigation was 5.67%⁶.89%and 15.35%¹8.73%higher than that of surface drip irrigation and control treatment,which enhanced the photosynthesis of maize.The average daily stomatal conductance was 13.31%¹3.73%and 25.51%³2.22%higher than surface drip irrigation and control treatment,which enhanced the gas exchange capacity of the leaves;Film drip irrigation has little effect on the average intercellular CO₂ concentration of corn.The daily average transpiration rate of surface drip irrigation was about 12%higher than that of film drip irrigation,which was 8.66%²0.74%higher than that of the control treatment.The film drip irrigation weakened the transpiration of maize;The film drip irrigation slightly increased the water use efficiency of the single leaf;The stomatal conductance and transpiration rate were positively correlated with the net photosynthetic rate,and the intercellular CO₂ concentration was negatively correlated with the net photosynthetic rate.3.Effect of film drip irrigation on maize growth,photosynthetic products and water use?1?The plant height and stem diameter of maize showed a rapid growth during jointing stage,and the heading stage was basically stable;The plant height was affected by rainfall,and the dry year was characterized by film drip irrigation>surface drip irrigation>control treatment;Film drip irrigation is conducive to the increase of stem diameter.?2?Film drip irrigation is beneficial to increase the photosynthetic potential,light receiving ability and source supply capacity,chlorophyll accumulation and leaf moisture retention of maize;Film drip irrigation increased the net assimilation rate of corn,which was 5.89%³1.36%and 9.66%³3.39%higher than the surface drip irrigation and control treatment;Providing a good environment for photosynthetic material accumulation and stem and leaf dry matter transport;The total translocation of stems and leaves was 14.90%¹7.44%and 62.87%⁸9.49%higher than surface drip irrigation and control treatment.?3?The economic yield of film drip irrigation is 13.66%²0.10%and 39.56%⁴3.88%higher than surface drip irrigation and control treatment;WUE was 26.05%²9.72%and26.60%³8.53%higher than surface drip irrigation and control treatment.